Exam 350-701 topic 1 question 691 discussion

An organization has had some malware infections recently and the management team wants to use Cisco Secure Firewall to enforce file policies to prevent malicious files from being downloaded. The SHA-256 hash value of all files traversing the firewall must be calculated and compared to the hash values of known malware code. Which file rule action is used to block only the files that are confirmed to be malware?